Triticum aestivumandLolium multifloruminteraction during drought

Abstract

A greenhouse experiment compared the vegetative growth in pure cultures and mixtures of winterTriticum aestivumcultivar ‘Mit’ andLolium multiflorumcultivar ‘Marshall’ in continuously watered controls and drought treatments. ControlL. multiflorumin pure culture 14 wk after planting produced more leaf area, tillers, and dry weights of stem and root than controlT. aestivumin pure culture. The greater seed size, larger initial leaf area, and height allowedT. aestivumto produce greater final leaf area and dry stem weight in control mixtures thanL. multiflorum.Watering following drought shifted the relative performance of the two species in pure cultures and mixtures compared to controls. The ability ofT. aestivumto maintain a greater leaf expansion rate during drought and a greater leaf area afterward thanL, multiflorumallowedT. aestivumto attain greater growth thanL. multiflorumin pure cultures exposed to temporary drought followed by watering. Conversely, drought and its relief enhanced the relative competitiveness ofL. multiflorumcompared to controls in mixtures withT. aestivum.During 4 wk of watering following the drought,L. multiflorumin mixtures grew vigorously and was similar toT. aestivumin all measures except in height and dry stem weight. Thus,L. multiflorumwas similar in root growth withT. aestivumin control and drought mixtures and had its aboveground competitiveness amplified by the cycle of drought and watering in this study. There was no evidence of an allelopathic interaction between the two species.